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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-12-07 14:31:33 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-12-07 14:36:21 +0100 |
| commit | b18cc3de00ec3442cf40ac60787dbe0703b99e24 (patch) | |
| tree | 70db9244d8ecf7126726510af587e65b4eae4574 /kernel/trace/ring_buffer.c | |
| parent | 1f759d328f6d8c06b5db55374b028565187deaca (diff) | |
| download | lwn-b18cc3de00ec3442cf40ac60787dbe0703b99e24.tar.gz lwn-b18cc3de00ec3442cf40ac60787dbe0703b99e24.zip | |
tracing/rb: Init the CPU mask on allocation
Before commit b32614c03413 ("tracing/rb: Convert to hotplug state machine")
the allocated cpumask was initialized to the mask of online or possible
CPUs. After the CPU hotplug changes the buffer initialization moved to
trace_rb_cpu_prepare() but the cpumask is allocated with alloc_cpumask()
and therefor has random content. As a consequence the cpu buffers are not
initialized and a later access dereferences a NULL pointer.
Use zalloc_cpumask() instead so trace_rb_cpu_prepare() initializes the
buffers properly.
Fixes: b32614c03413 ("tracing/rb: Convert to hotplug state machine")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20161207133133.hzkcqfllxcdi3joz@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a7a055f167c7..89a2611a1635 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1297,7 +1297,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags, if (!buffer) return NULL; - if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL)) + if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL)) goto fail_free_buffer; nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE); |